Device for cutting and cleaning commutator grooves



Dec. 29, 1959 w. H. RHINDRESS 2,913,851

DEVICE FOR CUTTING AND CLEANING COMMUTATOR GROOVES Filed April 25,1956

INVENTOR. Wfzerflfin dress Any.

ate ermit) AND" COMMUTATORGROVES Walter H. RhindressyBraintree, -Mass. Appli'ition April 25, 1956'; 'snai No; 580,531

1 Claim. oust- 1st control of a motor driven cutter of the *rotary saw Another object 'of the instant invention is the provision of means for undercutting commutator-segments, which means are readily portable.

Another object is the provision of a commutator cutter comprising means for readily adjusting the depth of cut.

A further object of the instant invention is the provi- 'sion' ofa commutator cutter comprising ineans fo'r readily adjusting and limiting the length"of-cut.

Stillanoth'er object of the instant invention is the provision "of acomrnutator cutter which is extremely han'dy in use sinceit may bereadily received 'by a vise, fastened to a workbench or attached to any wooden base support.

A further object is the provision of a device of the character described capable of accommodating a large range of armature sizes.

And still a further object is the provision of means for undercutting commutator segments, which means are relatively simple and economically feasible to manufacture but which nevertheless are durable and practical for everyday use.

Other objects, features and advantages of the invention will become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.

In the drawings which illustrate the best mode presently contemplated by me for carrying out my invention:

Fig. 1 is a side elevation of a device constructed in accordance with the instant invention;

'Fig. 2 is an end view thereof;

Fig. 3 is a section taken on line 33 of Fig. 2; and

Fig. 4 is a section taken on line 4-4 of Fig. 2.

It has been found desirable to provide a device for simplifying the operation of cutting and cleaning commutator grooves. Therefore, there has been provided in accordance with the instant invention an apparatus which comprises a motor driven rotary saw, means for mounting same and for mounting the commutator to be worked, and means for readily adjusting the depth of cutting and the length of cut. The structure is highly compact and hence is portable, a feature of high desirability in apparatus of this kind, since the structure may be readily mounted on any workbench support or in any vise. As will becomeapparent as the description of my invention hereinafter proceeds, my invention is capable of rapidly and effectively cutting or cleaning the grooves between commutator segments, or in fact, any grooves longitudinally disposed on a cylindrical shaft or body.

Referring to the drawings, my invention comprises an upstanding support 10, preferably of cast iron or the scribed.

like, provided along one surface thereof" with a gv -gioevia 16 having conventional {commutator segments '18." Ad

.justable clamping means 20 'o'ver'lie the 'V groove F 12 to securely retain the shaft end"1"4"therein;" as willbeseen most clearly in- Fig. 2. I prefer-that my clamping mea s at one endthereof'in engagement'with the side surfac'e of support 10. A threaded stud 24 extndsfrom thesup Port through 'a"suitable aperture "in the clamp 20 the jaws-30 of a viseywherebyto fixedly maintainthe apparatus in'position. v I

Pivotally mounted to a portion 32,- which also integrally and laterally extends :from'the support 10, is anarn'r structure generally designated ar'34. The arm 34 preferably comprises'a-bifurcated member 36 whichis pivotally-attached to the extension 32 asat 38 and 40. A handle 42- 'may be provided for imparting pivotal "movement to the arm 34 for reasons "hereinafter to be de- I The bifurcated element 36 has'pivotally attachedthereto as at 44 and 46 a lug" member'-"48:which' carries' an integral, upwardlyextending supporting *bracket' 50 and an integral, downwardly depending:arm52. Thebra'cket 50 is adapted to mount by any desirable means, such as screws 54 or the like, a small power motor 56, the shaft 5 8 of which carries a rotary saw cutter 60.

Referring to Figs. 1 and 2, it will be seen that the depending arm 52 is in substantial vertical alignment with the aforedescribed surface 28, and said depending arm is provided with a knurled adjusting screw 62 extending through a suitable threaded aperture provided therein. A lock nut 64 may be provided for maintaining the screw 62 in its desired position. As will be obvious, the screw 62 is adapted to make engagement with the aforedescribed surface 28 whereby to limit inward pivotal movement of the cutter carrier structure theretowards. More specifically, when handle 42 is pivoted from the dotted-line position of Fig. 4 to the full-line position shown therein, the pivotal movement of the arm assembly 34 will result in straight linear movement of the cutter carrier structure due to the pivotal association thereof with respect to the arm assembly or, more specifically, due to its pivotal attachment thereto as at 44, 46. The shank end of screw 62 engages the surface '28 and is adapted to slide therealong during the linear movement of the cutter carrier structure whereby to act as guide means therefor. Also, by adjusting the screw 62, the relative position of the cutter carrier structure, and more specifically, the motor-driven rotary saw 60 with respect to commutator segments 18 may be varied. Hence, by rotating the screw 62 in a clockwise direction, a more shallow cut will be obtained; while conversely, rotation thereof in a counter-clockwise direction will result in a deeper commutator groove being cut.

Means are also provided for limiting the stroke of pivotal movement of the arm assembly 34 and thereby limiting the longitudinal stroke of the rotary saw 60. This is important since it prevents inadvertent running of the cutter beyond the inner end 66 of the commutator segments 18. This means preferably takes the form of an angularly disposed screw 68 which extends through cross piece 70 of bifurcated member 36 and is adapted PQi'teritedeDecPZQ; 1959 to make engagement with the lateral surface 72 of carrier lug 48 after a predetermined degree of rotation. In other words, the screw 68 is preferably spring loaded as at 74, and it will be obvious that in order to shorten the stroke of the arm assembly 34, and accordingly, that of the cutter 60, it is only necessary to further thread in screw 68. If desired, a small abutment 76 may be provided on surface 72 to be engaged by the shank end of the screw 68.

In operation and use, it is simply necessary to clamp the armature to be worked in position by means of the clamping structure 20 as aforedescribed, said clamping structure preferably receiving therein the shaft end of the armature. If the commutator grooves have already been formed and are simply to be cleaned, it will be understood that the armature will be clamped into position so that a groove is in vertical alignment with the cutter means 60. The necessary adjustments for depth of cut and length of stroke are then made. Handle 42 is then rotated from the dotted-line position of Fig. 4 to the full-line position therein whereby to effect the desired cutting operation. It Will be understood that during this movement, the shank end of the screw 62 slides along surface 28, thereby providing the necessary guide means for the linear movement of the cutter 60 which, of course, is all the time being power rotated by the motor 56. As soon as the cut is completed, clamp 20 is loosened, and the armature is rotated slightly to bring the next commutator groove in proper vertical alignment, and then the operation is again repeated. The operation for initially cutting grooves would proceed in an identical manner.

While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made ,without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claim.

I claim:

A device of the character described comprising a fixed upstanding support having an elongated portion extending laterally therefrom, adjustable clamping means carried by said support for receiving an armature shaft end whereby the armature is fixedly maintained in substantially parallel relation to said elongated portion, an arm pivotally mounted on said support for pivotal movement in a direction lengthwise of said armature, a cutter carrier pivoted to said arm at a point spaced from said arm mounting whereby pivotal movement of said arm is adapted to result in movement of said cutter carrier lengthwise of said armature, a rotary saw on said cutter carrier for making engagement with said armature, a motor on said cutter carrier for rotating said saw, the weight of said motor simultaneously functioning to maintain said saw in proper engagement with said armature during pivotal movement of said arm, and an adjustable screw mounted on and extending from said carrier into engagement with said laterally extending elongated portion whereby to enable selective regulation of depth of cut during operation of the device and simultaneously to provide guide means during pivotal movement of said arm.

References Cited in the file of this patent UNITED STATES PATENTS 1,064,715 Dickenson June 17, 1913 1,472,365 Jordan Oct. 30, 1923 2,119,929 Schmitt June 7, 1938 2,146,458 Willard et al. Feb. 7, 1939 2,170,389 Payne Aug. 22, 1939 

